It's the same reason why it seems religiosity is prevalent in african americans.

(0. You can interpret any religious text to mean whatever it is that you want.)
1. women were/are an oppressed visible group of people. Christianity lauds suffering, justifying it as noble, and offering salvation to those that suffered.
2. prevents an oppressed visible group of people from further being oppressed due to irreligiosity.

The Bible verses about how women should be silent and be homemakers are what drove me away from God. I tried so hard to study those verses and be gentle and modest, but I always had things to say. And they were even edifying things! But I wasn't allowed to give a lesson or lead a song and it broke my heart. So I started to ask why God would give me this ability and desire, but command me not to do anything with it. People told me I should raise children, that would be the way to use my abilities. But being a mother is literally the last thing in the world I ever want to do, so I drifted away because I got really tired of being told to get married and obey my husband.

Feminism and acceptance of homosexuality (plus bi, plus whatever else) is going to continue to drive people away form the church. Ultimately, most people create their own morals based on culture and then justify it through their religion instead of the other way round.